Resin composition curbable with an active energy ray containing epoxy resin and monomer with ethylenically unsaturated bond

ABSTRACT

An improved active energy ray-curing resin composition comprising (i) a graft copolymerized polymer having a number average molecular weight of 5,000 or more and a weight average molecular weight of 50,000 or less: (ii) a linear polymer having a number average molecular weight of 5,000 or more and a weight average molecular weight of 350,000 or less and having a glass transition temperature of 60° C. or more: (iii) an epoxy resin containing at least one compound having one or more epoxy groups in one molecule, (iv) a monomer having an ethylenically unsaturated bond and (v) a polymerization initiator capable of generating a Lewis acid by irradiation of an active energy ray. The resin composition can be desirably cured with an active energy ray such as ultraviolet ray or electron beam and it is capable of being laminated in a desired pattern on a copper-coated laminate for use as a printed board or on a plate of metal, glass, ceramics or plastic.

FIELD OF THE INVENTION

This invention relates to a resin composition curable with an activeenergy ray such as ultraviolet ray or electron beam. More particularly,it relates to an improved resin composition curable with said activeenergy ray which is capable of being laminated in a desired pattern on acopper-coated laminate for use as a printed board or on a plate ofmetal, glass, ceramics or plastic.

BACKGROUND OF THE INVENTION

In recent years, there have been often used various resin compositionscurable with an active energy ray in coatings or inks, or as a sealingmaterial, as a resist material, as a material for forming a protectivefilm or as a material for forming a pattern. As such resin compositions,for use in forming a protective film for printed wiring board or for useas a resist material for forming a wiring pattern therefor, there areknown, for example, a dry film resist containing a high molecularmaterial capable of forming a film under the trade name of RISTON(produced by Du Pont Japan Ltd.) and a thick film liquid resistaccording to photographic method under the trade name of PROBIMER(produced by Ciba Geigy Co.).

These known resin compositions comprise mainly (a) high molecularmaterials contributing to formation of a film or a dry coating and (b) amaterial curable with an active energy ray. And for these resincompositions, their adhesiveness with a substrate, their developingproperties for the formation of a pattern, their durability, paintingproperty and drying property as a paint film are varied depending uponthe kinds and the molecular structures of said high molecular materials(a). Therefore, when such resin composition is used aiming at providingthe above properties as desired, the kinds of the high molecularmaterials (a) and the molecular design among the components are properlydetermined so as to meet the requirements.

However, any of the known resin compositions curable with an activeenergy is still not sufficient in view of the adhesiveness with varioussubstrates even in the case where it is so designed in the above way.

In order to solve this problem, there have been made proposals to add anauxiliary capable of forming a complex with a metal such as a specificheterocyclic compound or a coupling agent to such resin composition,whereby improving its adhesiveness with a metallic substrate asdisclosed in Japanese Laid-open Patent Applications No. 5934/1976 andNo. 24035/1983.

However, there is still an unsolved problem in the case of any of theseproposals, that the additive will cause oxidation or corrosion on theresin composition after the lapse of time.

Other than the above proposals, there has been proposed a high molecularmaterial comprising a graft copolymerized polymer having polar groups onits graft chains aiming at obtaining a cured composition exhibiting asufficient adhesiveness with a substrate without addition of suchadditive as mentioned above by Japanese Lain-open Patent Application No.283645/1986. The resin composition curable with an active energy raycontaining said high molecular material to be provided by thispublication is such that makes it possible to realize an improvement inthe adhesiveness of the resulting paint film with a substrate and alsoin its durability without using such additive as mentioned above.However, even for such resin composition as described in the abovepublication, there still remains the unsolved problem of how todetermine the molecular structures for the high molecular weightmaterials to be used in preparing resins having the desired properties.In fact, in general, it is technically difficult to synthesize adesirable graft copolymerized polymer so that it has a predeterminedmolecular weight and a predetermined content for the graft chains and ithas a desired weight average molecular weight in the range from 50,000to 350,000.

In order to provide desired enhancement in the developing propertiesupon formation of a pattern, in other words, in the dissolving rate ofunpolymerized part, the swelling of polymerized part, the sensitivity asa result of these factors, the sharpness of the resulting pattern andthe controlling ability of the resolution, it is necessary for thenumber average molecular weight of the high molecular material involvedto be not excessively small. In the case of a graft copolymerizedpolymer, to connect a plurality of graft chains having a lengthsufficient enough to provide an effective adhesiveness with its trunkchain of a relatively large molecular weight to thereby make theresulting graft copolymerized polymer to have a desired number averagemolecular weight is generally recognized as being difficult because ofsteric hindrance in this technical field.

In the case where the number average molecular weight of the highmolecular material involved is excessively small, when a pattern isformed using such high molecular material, there are limits for thedeveloping properties, that is, the dissolving rate of unpolymerizedpart, the swelling of polymerized part, the sensitivity as a result ofthese factors, the sharpness of the resulting pattern and thecontrolling allowance of the resolution.

SUMMARY OF THE INVENTION

This invention has been accomplished in view of the problems asdescribed above and an object of this invention is to provide animproved resin composition curable with an active energy ray such asultraviolet ray or electron beam which is capable of being laminated ina desired pattern on a copper-coated laminate for use as a printed boardor on a plate of metal, glass, ceramics or plastic.

Another object of this invention is to provide an improved resincomposition curable with an active energy ray which exhibits anexcellent adhesiveness with a substrate without addition of anyauxiliary.

A further object of this invention is to provide an improved resincomposition curable with an active energy ray which exhibits excellentdeveloping properties upon formation of a pattern.

A still further object of this invention is to provide an improved resincomposition curable with an active energy ray which may be easilycontrolled so as to exhibit desired properties upon applicationpurposes.

DETAILED DESCRIPTION OF THE INVENTION

The resin composition curable with an active energy ray to attain theabove objects of this invention is one that comprises:

(i) a graft copolymerized polymer having a number average molecularweight of 5,000 or more and a weight average molecular weight of 50,000or less which comprises a trunk chain composed mainly of structuralunits derived from at least one monomer (hereinafter referred to as"monomer A") selected from the group consisting of alkyl methacrylates,acrylonitrile and styrene and has graft chains having structural unitsderived from at least one monomer (hereinafter referred to as "monomerB") selected from the group consisting of the monomers represented bythe following formula I and other monomers presented by the formula II:##STR1## (wherein R¹ is hydrogen or an alkyl or hydroxyalkyl grouphaving 1 to 3 carbon atoms, R² is hydrogen or an alkyl or acyl grouphaving 1 to 4 carbon atoms which may have hydroxy group, R³ is an alkylgroup having 2 to 6 carbon atoms, a halogen-substituted alkyl grouphaving 2 to 6 carbon atoms, an alkylether group represented by theformula:

    --CH.sub.2n O--CH.sub.2m

(wherein 2≦m+n≦6, n≠0 and m≠0), or a phenylalkyl group represented bythe formula: ##STR2## (wherein 2≦m+n≦4, or the case where n=0 or m=0 iscontained), added to said trunk chain; (ii) a linear polymer having anumber average molecular weight of 50,000 or more and a weight averagemolecular weight of 350,000 or less and having a glass transitiontemperature of 60° C. or more which comprises structural units derivedfrom at least one monomer (hereinafter referred to as "monomer C")selected from the group consisting of methyl methacrylate, ethylmethacrylate, isobutyl methacrylate, t-butyl methacrylate, benzylmethacrylate, acrylonitrile, isobornyl methacrylate, isobornyl acrylate,tricyclodecaneacrylate, tricyclodecane methacrylate,tricyclodecaneoxyethyl methacrylate, styrene, dimethylaminoethylmethacrylate and cyclohexyl methacrylate and other structural unitsderived from at least one monomer (monomer B) selected from the groupconsisting of the monomers represented by said formula (I) and themonomers represented by said formula (II);

(iii) an epoxy resin containing at least one compound having one or moreepoxy groups in one molecule;

(iv) a monomer having an ethylenically unsaturated bond; and

(v) a polymerization initiator capable of generating a Lewis acid byirradiation of an active energy ray.

In constituting the above graft copolymerized copolymer (i), specificexamples of the monomers to be used for constitution of the trunk chainare such that the main component comprises one or more of alkylmethacrylate, acrylonitrile and styrene as described above. As for themonomers to be used for constitution of the graft chain, in addition tothe monomer selected from those represented the foregoing formulas I andII, it is possible to together use a polar monomer selected from thegroup consisting of acrylic monomers containing amino group oralkylamino group, acrylic or vinyl monomers containing carboxyl group,N-vinylpyrrolidone and its derivatives, and vinylpyridine and itsderivatives, in case where necessary. In addition, it is possible to usea hydrophobic monomer as the component of the copolymerization in anamount of about 25 mol % or less.

The above graft copolymerized polymer (i) to be used in the compositionof this invention can be prepared according to the known methods,specifically by various methods as disclosed in "Base and Application ofPolymer Alloy" p.10-35 (edited by Polymer Society of Japan, published byTokyo Kagaku Dojin K.K., 1981). Examples of these methods include (1)the chain transfer method, (2) the method by use of radiation, (3) theoxidation polymerization method, (4) the ion graft polymerization methodand (5) macromonomer method.

In accordance with any of these methods, the above graft copolymerizedpolymer (i) can be properly prepared using the foregoing monomers A andB under proper polymerization conditions which make it possible toobtain a desired graft copolymerized polymer having a number averagemolecular weight of 5,000 or more and a weight average molecular weightof 50,000 or less.

Among the above methods of (1) to (5), the methods of (4) and (5) arepreferred since the lengths of the graft chains may be easily uniformed.And, the macromonomer method of (5) is most preferred in view that it isadvantageous in design of materials.

The foregoing linear polymer (ii) may be properly prepared in accordancewith the conventional polymerization method using the foregoing monomerC as the main component and also using the foregoing monomer B underproperly selected polymerization conditions which permit production of alinear polymer having a number average molecular weight of 50,000 ormore and a weight average molecular weight of 350,000 or more and havinga glass transition temperature of 60° C. or more.

In this case, as for the monomer B,i.e. at least one monomer selectedfrom the group consisting of the monomers represented by the foregoingformula (I) and the monomers represented by the foregoing formula (II),it is preferred to add the monomer B in an amount of 5 to 30 mol % forthe following reasons. That is, when more than 30 mol % of the monomer Bis incorporated into a linear polymer to be obtained, there aredisadvantages that the polar group content in a cured paint film will beundesirably heightened and because of this, any improvement cannot beattained in its adhesiveness with a substrate, and in addition to this,the resulting cured film will be such that is poor in the water proof.On the other hand, when less than 5 mol % of the monomer B isincorporated into a linear polymer to be obtained, not only theadhesiveness with substrate but also the effects of a paint film as thebinder will be insufficient.

In order for the resulting linear polymer to have a high glasstransition temperature and to contribute in heightening the water prooffor the resulting cured film, among the foregoing monomers C,methylmethacrylate, isobornylmethacrylate, isobornylacrylate,tricyclodecaneacrylate or tricyclodecanemethacrylate is most desired.

The foregoing epoxy resin (iii) which contains at least one compoundhaving one or more epoxy groups in one molecule to be used in the resincomposition according to this invention is a component which permits thesaid resin composition to exhibit high sensitivity and satisfactorycurability in the presence of the foregoing polymerization initiator (v)with the action of an active energy ray and in addition thereto, impartsbetter adhesiveness with a substrate, water proof, resistance againstchemicals, dimensional stability, etc., to the resulting cured filmconstituted with the said resin composition, when it is formed byapplying the said resin composition in liquid state on a substrate ofglass, plastics, ceramics, etc., followed by curing, or when it is usedin the form of a dry film adhered on a substrate.

This is not a particular limitation for the epoxy resin (iii) as long asit is an epoxy resin that contains at least one kind of compound havingone or more epoxy groups in one molecule.

However, in order for the resulting resin cured film from the resincomposition of this invention to have desired resistance againstchemicals, mechanical strength and high durability as a structuredmember, in order to improve the resolution of a pattern comprising theresin cured film to be formed and also in order to improve the workefficiency at the time of forming various patterns comprising the resincured film on a substrate, it is desired to use an epoxy resincontaining at least one compound having two or more epoxy groups in onemolecule.

Examples of such epoxy resin containing two or more epoxy groups in onemolecule include epoxy resins as represented by the bisphenol A type,novolac type, alicyclic type, or polyfunctional epoxy resins such asbisphenol S, bisphenol F, tetrahydroxyphenylmethane tetraglycidyl ether,resorcinol diglycidyl ether, glycerine triglycidyl ether,pentaerythritol triglycidyl ether, isocyanuric acid triglycidyl etherand epoxyurethane resins represented by the following formula III:##STR3## (wherein R⁴ represents an alkyl group or an oxyalkyl group, R⁵represents ##STR4## or an alkyl group), and mixtures of two or more ofthem.

Specific examples of these polyfunctional epoxy resins include those asmentioned in the following. That is, the bisphenol A type epoxy resinmay be, for example, Epicoat 828, 834, 871, 1001, 1004 (trade names,produced by Shell Chemical Co.), DER 331-J, 337-J, 661-J, 664-J, 667-J(produced by Dow Chemical Co.), and Epicrone 800 (trade name, producedby Dainippon Ink Kagaku K.K.), etc. The novolac type epoxy resin may be,for example, Epicoat 152, 154, 172 (trade names, produced by ShellChemical Co.), Allaldite EPN 1138 (trade name, produced by Ciba GeigyCo.), DER 431, 438, and 439 (trade names, produced by Dow ChemicalCo.),etc. The alicyclic epoxy resin may be, for example, AralditeCY-175, -176, -179, -182, -184, -192 (trade names, produced by CibaGeigy Co.), Chissonox 090, 091, 092, 301, 313 (trade names, produced byChisso K.K.), CYRACURE 6100, 6110, 6200 and ERL 4090, 4617, 2256, 5411(trade names, produced by Union Carbide Co.) etc. The polyglycidyl etherof aliphatic polyhydric alcohol may be, for example, ethyleneglycoldiglycidyl ether, polyethyleneglycol diglycidyl ether, propyleneglycoldiglycidyl ether, polypropyleneglycol diglycidyl ether, neopentylglycoldiglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerine diglycidylether, trymethylolpropane triglycidyl ether, diglycidyl ether ofhydrogenated bisphenol A, 2.2-dibromoneopentylglycol diglycidyl ether,etc.; the polyglycidyl ether derived from aromatic polyhydric alcoholmay be, for example, diglycidyl ether of an addition product ofbisphenol A added with 2 to 16 mols of alkyleneoxide, a diglycidyl etherof an addition product of bisphenol F added with 2 to 16 mols ofalkylenoxide, a diglycidyl ether of an addition product of bisphenol Sadded with 2 to 16 mols of alkyleneoxide.

As the foregoing compound having an epoxy group in one molecule, therecan be mentioned olefine oxide, octylene oxide, butylglycidyl ether,glycidylmethacrylate, acrylglycidyl ether, styrene oxide, phenylglycidylether, n-butylphenolglycidyl ether, 3-pentadecylphenylglycidyl ether,cyclohexane vinyl monoxide, α-pinene oxide, glycidylesters oftert-carboxylic acids, and mixture of these compounds.

The monofunctional epoxy resins comprising the above compounds may beselectively used alone or in combination with the foregoingpolyfunctional epoxy resin.

The foregoing monomer (iv) having an ethylenically unsaturated bond tobe used in the resin composition according to this invention is acomponent for permitting the said composition to exhibit curability withan active energy ray, particularly imparting excellent sensitivity to anactive energy ray to the said composition, similarly as theabove-mentioned epoxy resin (iii). The said monomer (iv) shouldpreferably have a boiling point of 100° C. or higher under atmosphericpressure, having preferably two or more ethylenically unsaturated bonds,and various known monomers curable by irradiation of an active energyray can be used.

Specific examples of such monomer having two or more ethylenicallyunsaturated bonds include (a) acrylic acid esters of methacrylic acidesters of polyfunctional epoxy resins having two or more epoxy groups inone molecule, (b) acrylic acid esters or methacrylic acid esters ofalkyleneoxide addition products of polyhydric alcohols, (c) polyesteracrylates having acrylic acid ester group at the terminal ends of themolecular chains of polyesters having molecular weights of 500 to 3000comprising dibasic acid and dihydric alcohol, (d) the reaction productsbetween polyisocyanates and acrylic acid monomers having hydroxylgroups. The above monomers (a)-(d) may be urethane-modified productshaving urethane bonds in the molecules.

Examples of the monomer belonging to (a) include acrylic acid ormethacrylic acid esters of polyfunctional epoxy resins to be used forformation of the foregoing epoxy resin (iii).

Examples of the monomer belonging to (b) include ethyleneglycoldi(meth)acrylate, diethyleneglycol di(meth)acrylate, polyethyleneglycoldi(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethyleneglycoldi(meth)acrylate, pentaerythritol tri(meth)acrylate and the like, andthose known under the trade names of KAYARAD HX-220, HX-620, D-310,D-320, D-330, DPHA, R-604, DPCA-20, DPCA-30, DPCA-60, DPCA-120 (allproduced by Nippon Kayaku K.K.), and also those known under the tradenames of NK ester BPE-200, BPE-500, BPE-1300, A-BPE-4 (all produced byShin Nakamura Kagaku K.K.), etc., may also be used.

The monomers belonging to (c) may be exemplified by those known underthe trade names of Aronix M-6100, M-6200, M-6250, M-6300, M-6400,M-7100, M-8030, M-8060, M-8100 (all produced by Toa Gosei Kagaku K.K.).Examples of the monomer belonging to (c) and having urethane bonds ofpolyester include those known under the trade names of Aronix M-1100,Aronix M-1200, (both produced by Toa Gosei Kagaku K.K.).

The monomers belonging to (d) may include the reaction products betweenpolyisocyanate such as tolylene diisocyanate, isophorone diisocyanate,hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysinediisocyanate, diphenylmethane diisocyanate or the like with a hydroxylcontaining acrylic monomer, and it is possible to use the reactionproducts having (meth)acrylic acid esters containing hydroxyl group(s)added to polyisocyanate compounds known under the trade names ofSumidule N (buret derivative of hexamethylene diisocyanate), Sumidule L(trimethylolpropane modified product of tolylene diisocyanate) (allproduced by Sumitomo Bayer Urethane K.K.), etc. The hydroxyl containingacrylic monomer as herein mentioned may include typically (meth)acrylicacid esters, preferably hydroxyethyl (meth)acrylate, hydroxypropyl(meth)acrylate. It is also possible to use other acrylic monomerscontaining hydroxyl group(s), particularly those represented by theforegoing formula I to be used for the graft chains in the case of theforegoing graft copolymerized polymer (i).

In addition to the monomers having two or more ethylenically unsaturatedbonds as mentioned above, it is also possible to use monomers havingonly one ethylenically unsaturated bond as mentioned below together withthese monomers.

To exemplify such monomers having one ethylenically unsaturated bond,there may be included, for example, carboxyl containing unsaturatedmonomers such as acrylic acid, methacrylic acid or the like; glycidylcontaining unsaturated monomers such as glycidyl acrylate, glycidylmethacrylate or the like; C₂ -C₈ hydroxyalkyl esters of acrylic acid ormethacrylic acid such as hydroxyethyl acrylate, hydroxyethylmethacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate or thelike; monoesters of acrylic acid or methacrylic acid withpolyethyleneglycol or polypropyleneglycol such as polyethyleneglycolmonoacrylate, polyethyleneglycol monomethacrylate, polypropyleneglycolmonoacrylate, polypropyleneglycol monomethacrylate or the like; C₁ -C₁₂alkyl or cycloalkyl esters of acrylic acid or methacrylic acid such asmethyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate,butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate,cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, propylmethacrylate, isopropyl methacrylate, butyl methacrylate, isopropylmethacrylate, butyl methacrylate, hexyl methacrylate, octylmethacrylate, lauryl methacrylate, cyclohexyl methacrylate or the like;other monomers such as styrene, vinyltoluene, methylstyrene, vinylacetate, vinyl chloride, vinyl isobutyl ether, acrylonitrile,acrylamide, methacrylamide, acrylic acid or methacrylic acid adduct ofalkylglycidyl ether, vinylpyrrolidone,dicyclopentenyloxyethyl(meth)acrylate, ε-caploractonemodifiedhydroxyalkyl(meth)acrylate, tetrahydrofurfulyl acrylate, phenoxyethylacrylate; and others.

By use of the above monomer (iv) having ethylenically unsaturated bonds,high sensitivity and satisfactory curability to an active energy ray canbe imparted to the resin composition for formation of a resin cured filmin this invention.

The foregoing polymerization initiator (v) capable of generating a Lewisacid with irradiation of an active energy ray to be used in the activeenergy ray curable resin composition according to this invention is acomponent for curing the epoxy resin (iii) as mentioned above with theaction of the Lewis acid, which permits the said resin composition toexhibit a high sensitivity and desired curability to an active energyray. As such a polymerization initiator (v), there may be preferablyused, for example, aromatic onium salt compounds having photosensitivitycontaining an element belonging to the groups VIa as disclosed inJapanese Patent publication No. 14278/1977 or aromatic onium saltcompounds having photosensitivity containing an element belonging to thegroup Va as shown in Japanese Patent publication No. 14279/1977 oraromatic halonium salts having photosensitivity as shown in JapanesePatent publication No. 147277/1977. These aromatic onium salt compoundsor aromatic halonium salts all have the characteristic of curing theepoxy resin (iii) by releasing a Lewis acid with irradiation of anactive energy ray.

The aromatic onium salt compounds having photosensitivity of the elementbelonging to the group VIa or the group Va may include typically thecompounds of the following formula IV:

    [(R.sup.3).sub.a (R.sup.4).sub.b (R.sup.5).sub.c X].sub.d.sup.+ [MQ.sub.e ].sup.-(e-f)                                              (IV)

(wherein R³ is a monovalent organic aromatic group, R monovalent organicaliphatic group selected from alkyl groups, cycloalkyl groups andsubstituted alkyl groups, R⁵ is a polyvalent organic group forconstituting heterocyclic or fused ring structure selected fromaliphatic groups and aromatic groups, X is an element belonging to thegroup VIa selected from sulfur, selenium and tellurium or an elementbelonging to the group Va selected from nitrogen, phosphorus, arsenic,antimony and bismuth, M is a metal or metalloid and Q is halogen, a isan integer of 0 to 3 when X is an element belonging to the group VIa oran integer of 0 to 4 when X is an element belonging to the group Va, bis an integer of 0 to 2, c is an integer of 0 or 1 when X is an elementbelonging to the group VIa or an integer of 0 to 2 when X is an elementbelonging to the group Va, f is an integer of 2 to 7 representing thevalence of M, e is an integer which is greater than f but not more than8, and the sum of a, b and c is 3 when X is an element belonging to thegroup VIa or 4 when X is an element belonging to the group Va, andd=e-f).

On the other hand, the photosensitive aromatic halonium salt may beexemplified by the following formula V:

    [(R.sup.6).sub.g (R.sup.7).sub.h X].sub.i.sup.+ [MQ.sub.j ].sup.-(k-l)(V)

(wherein R⁶ is a monovalent aromatic organic group, R⁷ is a divalentaromatic organic group, X is halogen, M is a metal or metalloid and Q ishalogen, respectively, g is an integer of 0 or 2 and h is an integer of0 or 1, with the sum of g and h being equal to 2 or the valence of X, ibeing equal to k-l, j is an integer of 2 to 7 which is equal to thevalence of M, and k is an integer greater than one but up to 8).

Specific examples of the photosensitive aromatic onium salt compoundscontaining an element belonging to the group VIa or the group Va mayinclude the photosensitive aromatic onium salts of the elementsbelonging to the group VIa as shown below: ##STR5## and photosensitivearomatic onium salts of the elements belonging to the group Va as shownbelow: ##STR6##

Specific examples of the photosensitive aromatic halonium salts include,for example: ##STR7##

In addition to the above polymerization initiator (iv), it is possibleto use a proper known hardener selected from polyamines, polyamides,acid anhydrides, boron trifluorideamine complexes, imidazoles, complexesof imidazoles with metal salts, in case where necessary.

The active energy ray curable resin composition according to thisinvention is one that is cured with irradiation of an active energy ray.In the case where there are used a graft copolymerized polymer (i)and/or a linear polymer (ii) respectively having photoloymerizabililyand an active energy ray with a wavelength of 250 nm to 450 nm, it isdesired to place a radical polymerization initiator having theproperties of being activated with the action of an active energy ray,forming organic free radicals and initiating radical polmerization inthe said resin composition.

Specific examples of such radical polymerization initiators includebenzyl ether: benzoin alkyl ethers such as benzoin isobutyl ether,benzoin isopropyl ether, benzoin-n-butyl ether, benzoin ethyl ether,benzoin methyl ether and the like; benzophenones such as benzophenone,4,4'-bis (N,N-diethylamino)benzophenone benzophenone methyl ether andthe like; anthraquinones such as 2-ethylanthraquinone,2-tertbutylanthraquinone and the like; xanthones such as2,4-dimethylthioxanthone, 2,4-diisopropylthioxathone and the like;acetophenones such as 2,2-dimethoxy-2-phenylacetophenone, α,α-dichloro-4-phenoxyacetophenone, p-tert-butyltrichloroacetophenone,p-tert-butyldichloroacetophenone, 2,2-diethoxyacetophenone,p-dimethylaminoacetophenone and the like; or hydroxycyclohexylphenylketone (e.g., Irugacure 184, produced by Ciba Geigy Co.),1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on (e.g. Darocure1116, produced by Merck Co.): 2-hydroxy-2-methyl-1-phenylpropane-1-on(e.g. Darocure 1173, produced by Merck Co.): etc., as preferable ones.

In addition to these radical polymerization initiators, amino compoundsmay be added as the photopolymerization accelerator.

The amino compounds to be used as the photopolymerization acceleratormay include ethanolamine, ethyl-4-dimethylaminobenzoate,2-(dimethylamino)ethylbenzoate, p-dimethylaminobenzoic acid n-amylester,p-dimethylaminobenzoic acid isoamyl ester, etc.

The constitutional ratios of the foregoing graft copolymerized polymer(i), linear polymer (ii), epoxy resin (iii), monomer (iv) andpolymerization initiator (v) for the active energy ray-curing resincomposition according to this invention are properly determined upon theapplication purpose.

In a preferred embodiment, the weight ratio of the graft copolymerizedpolymer (i) to the linear polymer (ii) is desired to be such that(i):(ii) is in the range of from 80:20 to 50:50 in parts by weight.

This situation is an important factor for the active energy ray-curingresin composition according to this invention to exhibit a desiredadhesiveness to a substrate based on the graft copolymerized polymer (i)and a desired patterning property based on the linear polymer (ii).

In addition to the above, the weight ratio of the sum of the graftcopolymerized polymer (i) and the linear polymer (ii) to the sum of theepoxy resin (iii) and the monomer (iv) is desired to be such that[(i)+(ii)]:[(iii)+(iv)] is in the range of from 100:50 to 100:200 inparts by weight.

The weight ratio of the epoxy resin (iii) to the monomer (iv) is desiredto be such that (iii):(iv) is in the range of from 25:75 to 75:25 inparts by weight.

The amount of the polymerization initiator (v) to be contained in theresin composition of this invention is desired to be such that[(i)+(ii)+(iii)+(iv)]:(v) is in the range of from 100:1 to 100:10 inparts by weight.

Further, in the case where the foregoing radical polymerizationinitiator or/and the foregoing photopolymerization accelerator is used,the sum amount (vi) of one of them or both of them is desired to be suchthat [(i)+(ii)+(iii)+(iv)]: (vi) is in the range of from 100:1 to 100:10in parts by weight.

The active energy ray-curing resin composition according to thisinvention may further contain additives such as catalysts forcondensation crosslinking, heat polymerization inhibitors, colorantssuch as dyes and pigments, fillers, heat stabilizers such ashydroquinone or paramethoxyphenol, adhesion promotors, plasticizers,extender pigments such as silica or talc, leveling agents of impartingcoating suitability, etc., if desired.

The condensation crosslinking catalyst may include sulfonic acids,typically p-toluenesulfonic acid, carboxylic acids such as formic acid,etc. The heat polymerization inhibitor may include hydroquinone andderivatives thereof, p-methoxyphenol, phenothiazine, etc. As thecolorant, there can be added oil-soluble dyes and pigments within therange which do not substantially prevent transmission of the activeenergy ray. As the filler, for enhancement of hardness of coating, aswell as for enhancement of coloration, adhesion, mechanical strength,there may be employed extender pigments, plastic fine particles, etc.,which are used in coating materials in general. As the adhesionpromotor, silane coupling agents, low molecular surfactants as inorganicsurface modifiers may be effectively used.

As the solvent to be used when employing the active energy ray-curingresin composition for formation of a resin cured film in the form of aliquid or when coating the composition on a plastic film which is a filmsubstrate in formation of a dry film, hydrophilic solvents such asalcohols, glycol ethers, glycol esters, etc., may be employed. Ofcourse, it is also possible to use mixtures comprising these hydrophilicsolvents as the main component, mixed optionally at appropriateproportions with ketones such as methyl ethyl ketone, methyl isobutylketone, etc., esters such as ethyl acetate, isobutyl acetate, etc.,aromatic hydrocarbons such as toluene, xylene, etc., and their halogenderivatives, aliphatic solvents containing chlorine such as methylenechloride, 1,1,1-trichloroethane, etc. These solvents can be also used asthe developer for the resin composition after patterning.

The active energy ray-curing resin composition according to thisinvention as explained above may be applied onto a substrate inaccordance with any of the conventional methods. Specific examples ofsuch method will be below illustrated:

(1) In the case of forming a cured film coat on a substrate, the activeenergy ray-curing resin composition is liquid state is applied onto thesubstrate to form a liquid coat thereon which is followed by evaporationto dryness, then the resultant dried coat is cured by irradiating itwith an active energy.

(2) In the case of forming a protective cured layer in the form of adesired pattern on a substrate, the active energy ray-curing resincomposition in liquid state is applied onto the substrate to form aliquid coat thereon which is followed by evaporation to dryness, theresultant dry layer is scanned with laser beam in a desired pattern, andthe unexposed portion is etched off with a proper solvent such as1,1,1-trichloroethane to thereby form a protective cured layer in theform of a desired pattern on the substrate.

(3) In the case of forming a protective cured layer coat in the form ofa desired pattern on a substrate, the active energy ray-curing resincomposition in liquid state is applied onto the substrate to form aliquid coat thereon which is followed by evaporation to dryness, aphotomask having a pattern with a desired shape which does not transmitany active energy ray is superposed on the resultant dry film layer,then exposure with an active energy ray is effected from above thephotomask, and the unexposed portion is removed by a proper solvent suchas 1,1,1-trichloroethane to thereby form a protective cured layer in theform of a desired pattern on the substrate.

(4) In the case of forming a photosensitive dry film and laminating saiddry film on a substrate, the active energy ray-curing resin compositionin liquid state is applied onto a polyethylene terephthalate film toform a liquid coat thereon which is followed by evaporation dryness,whereby obtaining a photosensitive dry film on the said polyethyleneterephthalate film, the resultant is laminate onto a substrate inaccordance with the conventional lamination method to obtain a laminate,and the photosensitive dry film as laminated on the substrate is curedby irradiating it with an active energy ray in the same way as in theabove method (1).

If the resulting cured photosensitive film is desired to have beenshaped in a desired pattern, the above dry film as laminated on thesubstrate is treated in the same way as the above method (2) or (3).

In the case where the active energy ray-curing resin composition is onethat contains the monomer represented by the foregoing formula (1), thecured film as obtained in any of the above methods (1) to (4) is desiredto be further subjected to heat-treatment at a temperature of 80° C. to200° C. to thereby condensedly cure it.

The active energy ray to be used for curing the active energy ray-curingresin composition of this invention or for the pattern exposure mayinclude ultraviolet rays (UV-rays) or electron beams which have widelybeen practically applied. As the UV-ray light source, there may beemployed high pressure mercury lamps, ultra-high pressure mercury lamps,metal halide lamps, etc., enriched in light with wavelength of 250 nm to450 nm, preferably those which can give a light intensity of about 1mW/cm² to 100 mW/cm² at the wavelength in the vicinity of 365 nm at adistance between the lamp and the material to be irradiated which ispractically permissible. The electron beam irradiation device is notparticularly limited, but a device having a dose within the range of 0.5to 20 M Rad is practically suitable.

PREFERRED EMBODIMENT OF THE INVENTION

The advantages of this invention are now described in more detail byreference to the following Examples, which are provided merely forillustrative purposes only, and are not intended to limit the scope ofthis invention.

EXAMPLE 1 1. Provision of each of the components (i) to (v) for thepreparation of a active energy ray-curing resin composition of thisinvention Preparation of a graft copolymerized polymer (i)

Radical chain transfer polymerization of 80 parts by weight of2-hydroxyethylmethacrylate and 20 parts by weight of butylacrylate wascarried out using thioglycollic acid as the chain transferring agent andazobisisobutyronitrile as the polymerization initiator to obtain anoligomer having a carboxyl group at the terminal end of the molecularchain.

This oligomer was reacted with glycidylmethacrylate to obtain amacromonomer having a methacryloyl group at one terminal end of themolecular chain. The result of the measurement by the known GPC methodgave a value of about 3,000 for the number average molecular weight ofthe resultant macromonomer.

Solution polymerization of 30 parts by weight of the said macromonomerand 70 parts by weight of methylmethacrylate was carried out in methylcellosolve solvent to thereby obtain a graft copolymerized polymerhaving a weight average molecular weight of about 40,000 and a numberaverage molecular weight of about 5,500.

A linear polymer (ii)

There was provided a linear acrylic copolymer obtained by polymerizingmethylmethacrylate. This linear acrylic copolymer is one that has anumber average molecular weight of about 70,000 and a weight averagemolecular weight of about 250,000.

An epoxy resin (iii)

There were provided the following two epoxy resins (iii)-(i) and(iii)-(2):

(iii)-(i): Epicoat 152 (trade name, produced by Yuka ShellepoxyK.K.)(epoxy resin of cresol novolac type: epoxy equivalent of 172-179)

(iii)-(2): Celloxide 2021 (trade name, produced by Daiseru KagakuK.K.)(epoxy resin of alicyclic type: epoxy equivalent of 128-145)

A monomer having an ethylenically unsaturated bond (iv)

There was provided the following acrylic ester: acrylic ester (100%esterificated) of Epicoat 828 (trade name, produced by Yuka ShellepoxyK.K.)(epoxy resin of bisphenol A type: epoxy equivalent of 183-193)

A polymerization initiator (v)

There were provided the following two polymerization initiators (v)-(1)and (v)-(2):

(v)-(1): the foregoing photosensitive aromatic onium salt (n)

(v)-(2): IRGACURE 651 (trade name, produced by Ciba Geigy Co.)[photopolymerization initiator for the above monomer (iv)]

2. Preparation of an active energy ray-curing resin composition of thisinvention

The above components (i) to (v)-(2) were well mixed by the weight ratiosas below shown in accordance with the conventional mixing technique tothereby obtain the active energy ray-curing resin composition, in whichthere were used the additives as below shown.

    ______________________________________                                        Component       Parts by weight                                               ______________________________________                                        (i)             50                                                            (ii)            50                                                            (iii)-(1)       50                                                            (iii)-(2)       20                                                            (iv)            50                                                            (v)-(1)         8                                                             (v)-(2)         10                                                            methyl cellosolve                                                                             200                                                           methylethyl ketone                                                                            100                                                           ______________________________________                                    

3. Preparation of a resin cured film

The thus obtained active energy ray-curing resin composition in liquidstate was applied onto the cleaned surface of a glass plate to form aliquid coat of about 80 μm in thickness, followed by air-dryness at 100°C. for 15 minutes to obtain a dry film of about 40 μm on the glassplate.

The glass plate having said dry film thereon was exposed to activeenergy rays (maximum irradiation energy: 100 mW/cm²) from an ultra-highpressure mercury lamp for 60 seconds. Thereafter, it was heat-treated at150° C. for 30 minutes.

The resultant was subjected to reflux treatment in 1% caustic sodaaqueous solution for 10 hours.

The thus obtained laminate was tested and as a result, it was found thatthe exposed (cured) resin film is firmly adhered to the glass plate, andthere were not observed any chloroisis or bulging phenomena on theresultant film even after storage for a long period of time.

EXAMPLE 2

The active energy ray-curing resin composition obtained in Example 1 wasapplied by the conventional bar coater onto the cleaned surface of aPyrex glass plate of 10 cm by 10 cm in size (trade name: Corning 7740.produced by Corning Glass Wear Co.), cleaned by way of ultrasoniccleaning in a cleaning liquid (trade name: Dafuron, produced by DaikinKohgyo K.K.), to form a liquid coat thereon, followed by air-dryness toobtain a dry film of about 50 μm in thickness in the same way as inExample 1.

Subsequently, on the dry film laminated on the glass plate, there waslaminated a polyethylenetere phthalate film (Lumirror-T type, producedby Toray K.K.) of 16 μm in thickness. Then, a mask for testing theresolution was superposed thereon.

The resultant was subjected to pattern exposure for 20 seconds using theconventional ultra-high pressure mercury lamp of generating collimatedUV ray, the luminous flux density of the UV ray from which is to be 10mW/cm² near 254 nm.

After completion of the exposure, the polyethyleneterephthalate film wasremoved. The remaining was engaged in spray-development with1,1,1-trichloroethane at 35° C. for 60 seconds, wherein the developmentwas effectively and stably proceeded and as a result, there wasprecisely reproduced a pattern of 150 μm line width and 150 μm in space.

After completion of the development, the glass plate having the cureddry film thereon was subjected to heat-treatment of 80° C. for 10minutes, and it was exposed to UV ray with 10 J/cm², followed byheat-treatment at 150° C. for 30 minutes.

As a result of conducting cross-cut tape removal test using a cellophanetape on the resultant, there was recognized 100/100 adhesion, and it wasfound that the cured dry film is firmly adhered to the glass plate.Further, the resultant was immersed in a NaOH aqueous solution of pH 12at 80° C. for 24 hours, washed with water and air-dried. Then, it wasagain subjected to the above cross-cut tape removal test. There was notobserved any reduction in the adhesion of the cured dry film with theglass plate.

EXAMPLE 3 1. Provision of each of the components (i) to (v) for thepreparation of an active energy ray-curing resin composition of thisinvention

Preparation of a graft copolymerized polymer (i)

The procedures for the preparation of the macromonomer in Example 1 wererepeated, except that there were used 50 parts by weight of2-hydroxyethylmethacrylate and 50 parts by weight ofbutoxymethylacrylamide, to thereby obtain a macromonomcr having amethacryloyl group at one terminal end of the molecular chain.

The result of the measurement by the known GPC method gave a value ofabout 2,000 for the number average molecular weight of the resultantmacromonomer.

Solution polymerization of 20 parts by weight of the said macromonomerand 80 parts by weight of methylmethacrylate was carried out in asolvent containing methyl cellosolve and methylethy ketone by the weightratio of 60:40 to thereby obtain a thermosetting graft copolymerizedpolymer having a number average molecular weight of about 5,000 and aweight average molecular weight of about 30,000.

A linear polymer (ii)

There was provided a linear acrylic copolymer obtained by polymerizingmethylmethacrylate and tricyclodecanmethacrylate in the molar ratio of70:30. This linear acrylic copolymer is one that has a number averagemolecular weight of about 60,000 and a weight average molecular weightof about 260,000.

An epoxy resin (iii)

There were provided the following two kinds of epoxy resins (iii)-(1)and (iii)-(2):

(iii)-(1): Epicoat 1001 (trade name, produced by Yuka ShellepoxyK.K.)(epoxy resin of bisphenol A type: epoxy equivalent of 450-500)

(iii)-(2): Celloxide 3000 (trade name, produced by Daiseru KagakuK.K.)(epoxy resin of alicyclic type: epoxy equivalent of 93.5)

A monomer having an ethylenically unsaturated bond (iv)

There was provided the following acrylic ester: acrylic ester (100%esterificated) of Epicoat 152 (trade name, produced by Yuka ShellepoxyK.K.)(epoxy resin of cresol novolak type: epoxy equivalent of 172-179)

A polymerization initiator (v)

There were provided the following two kinds of polymerization initiators(v)-(1) and (v)-(2):

(v)-(1): the foregoing photosensitive aromatic onium salt (n)

(v)-(2): IRGACURE 651 (trade name, produced by Ciba GeigyoCo.)[Photopolymerization initiator for the above monomer (iv)]

2 Preparation of an active energy ray-curing resin composition of thisinvention

The above components (i) to (v)-(2) were well mixed by the weight ratiosas below shown in accordance with the conventional mixing technique tothereby obtain the active energy ray-curing resin composition, in whichthere were used the additives as below shown.

    ______________________________________                                        Component       Parts by weight                                               ______________________________________                                        (i)             80                                                            (ii)            20                                                            (iii)-(1)       60                                                            (iii)-(2)       30                                                            (iv)            90                                                            (v)-(1)         8.5                                                           (v)-(2)         10                                                            methyl cellosolve                                                                             220                                                           methylethyl ketone                                                                            100                                                           ______________________________________                                    

3 Preparation of a protective resin cured film on a printed board

On a printed board comprising conductor circuit composed of 60 μm thickcopper foil formed on a glass cross epoxy resin substrate, there wasformed a liquid coat of the thickness to be 50 μm when dried by applyingthe resin composition in liquid state obtained in the above step 2 byway of the conventional roll coater. The liquid coat was then air-driedat 100° C. for 3 minutes.

After cooling, a solder mask pattern was superposed on the dry film andsubjected to pattern exposure for 35 seconds using the conventionalultra-high pressure mercury lamp of generating collimated UV ray, theluminous flux density of the UV ray from which is to be 7 mW/cm² near365 nm and the collimation amplitude is to be 3°. After completion ofthe exposure, the resultant was engaged in spray-development with1,1,1-trichloroethane at 20° C. for 50 seconds. The development wasstably proceeded and as a result, there was formed a clear pattern.After completion of the development, the cured dry film on the printedboard was air-dried and further irradiated with UV ray from the abovemercury lamp for 5 minutes, followed by heat-treatment at 150° C. for 15minutes to thereby complete the formation of a patterned resin curedprotective film on the printed board.

As a result of examining the resultant protective film, it was foundthat the film is excellent in the resistance against not only acids butalso alkalis and also in the resistance against other chemicals.

What we claim is:
 1. A resin composition curable with an active energyray comprising:(i) a graft copolymerized polymer having a numbermolecular weight of 5,000 or more and a weight average molecular weightof 50,000 or less which comprises a trunk chain composed mainly ofstructural units derived from at least one monomer selected from thegroup consisting of alkyl methacrylates, acrylonitrile and styrene andhas graft chains having structural units derived from at least onemonomer selected from the group consisting of the monomers representedby the following formula I and other monomers presented by the formulaII: ##STR8## (wherein R¹ is hydrogen or an alkyl or hydroxyalkyl grouphaving 1 to 3 carbon atoms, R² is hydrogen or an alkyl or acyl grouphaving 1 to 4 carbon atoms which may have hydroxy group, R³ is an alkylgroup having 2 to 6 carbon atoms, a halogen-substituted alkyl grouphaving 2 to 6 carbon atoms, an alkylether group represented by theformula:

    --CH.sub.2n O--CH.sub.2m

(wherein 2≦m+n≦6, n≠0 and m≠0), or a phenylalkyl group represented bythe formula: ##STR9## (wherein 2≦m+n≦4, or the case where n=0 or m=0 iscontained), added to said trunk chain; (ii) a linear polymer having anumber average molecular weight of 50,000 or more and a weight averagemolecular weight of 350,000 or less and having a glass transitiontemperature of 60° C. or more which comprises structural units derivedfrom at least one monomer selected from the group consisting of methylmethacrylate, ethyl methacrylate, isobutyl methacrylate, t-butylmethacrylate, benzyl methacrylate, acrylonitile, isobornyl methacrylate,isobornyl acrylate, tricyclodecaneacrylate, tricyclodecane methacrylate,tricyclodecaneoxyethyl methacrylate, styrene, dimethylaminoethylmethacrylate and cyclohexyl methacrylate and other structural unitsderived from at least one monomer in amounts from 5 to 30 mole percentselected from the group consisting of the monomers represented by saidformula (I) and the monomers represented by said formula (II); (iii) anepoxy resin containing at least one compound having one or more epoxygroups in one molecule; (iv) a monomer having (v) a polymerizationinitiator capable of generating a Lewis acid by irradiation of an activeenergy ray.
 2. The resin composition according to claim 1, wherein theweight ratio of said graft copolymerized polymer (i) to said linearpolymer (ii) to said linear polymer (ii) is such that (i):(ii) is in therange from 80:20 to 50:50.
 3. The resin composition according to claim 1or claim 2, wherein the weight ratio of the sum of said graftcopolymerized polymer (i) and said linear polymer (ii) to the sum ofsaid epoxy resin (iii) and said monomer (iv) is such that[(i)+(ii)]:(iii)+(iv)] is in the range from 100:50 to 100:200.
 4. Theresin composition according to claim 3, wherein the weight ratio of saidepoxy resin (iii) to said monomer (iv) is such that (iii):(iv) is in therange from 25:75 to 75:25.
 5. The resin composition according to claim1, wherein the weight ratio of the sum of said graft copolymerizedpolymer (i), said linear polymer (ii), said epoxy resin (iii) and saidmonomer (iv) to said polymerization initiator (v) is such that[(i)+(ii)+(iii)+(iv)]:(v) is in the range from 100:1 to 100:10.
 6. Theresin composition according to claim 1, wherein said polymerizationinitiator (v) comprises an aromatic halonium salt compound or anaromatic onium salt compound having photosensitivity containing anelement belonging to group VIa or group Va, of the periodic table.